198655556891 has 4 divisors (see below), whose sum is σ = 216715152984. Its totient is φ = 180595960800.

The previous prime is 198655556851. The next prime is 198655556903.

It is a happy number.

198655556891 is nontrivially palindromic in base 10.

198655556891 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 198655556891 - 2¹⁰ = 198655555867 is a prime.

It is not an unprimeable number, because it can be changed into a prime (198655556831) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 9029798030 + ... + 9029798051.

It is an arithmetic number, because the mean of its divisors is an integer number (54178788246).

Almost surely, 2^198655556891 is an apocalyptic number.

198655556891 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

198655556891 is a deficient number, since it is larger than the sum of its proper divisors (18059596093).

198655556891 is a wasteful number, since it uses less digits than its factorization.

198655556891 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18059596092.

The product of its digits is 116640000, while the sum is 68.

The spelling of 198655556891 in words is "one hundred ninety-eight billion, six hundred fifty-five million, five hundred fifty-six thousand, eight hundred ninety-one".